Minor alkaloids nornicotine

Precursors and Formation. Tobaccos used for commercial products in the U.S.A, contain between 0,5 and 2,7% alkaloids. Nicotine constitutes 85-95% of the total alkaloids (14,26,27). Important minor alkaloids are nornicotine, anatabine, anabasine, cotinine and N -formylnornicotine (Figure 6), Several of these alkaloids are secondary and tertiary amines and, as such, amenable to N-nitrosation. The N-nitrosated alkaloids identified to date in tobacco and tobacco smoke include N -nitrosonornico-tine (NNN), 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone (NNK) and N -nitrosoanatabine (NAT Figure 7). In model experiments, nitrosation of nicotine also yielded 4-(methylnitrosamino)-4-(3-pyridyl)butanal (NNA 28). 

Bush determined the four most important tobacco alkaloids (nicotine, nornicotine, anabasine and anatabine) using a 10 % DC 550 packed column on Chromosorb 60-80, and using isoquinoline as an internal standard. The alkaloids were extracted with benzene-chloroform (9 1) after treatment of the tobacco sample (1 g) with bariumhydroxide and water. The organic phase was concentrated and used for the gas chromatographic determination. Because of the great differences in the amounts of the minor alkaloids and nicotine in most tobacco samples, two extractions, each with an appropriate amount of internal standard, were required for a complete assay. The precision of the quantitative analysis on tobacco samples of different alkaloids is given in Table 5.6. 

The minor airborne tobacco alkaloids, nornicotine, myosmine and anabasine, did not interfere with nicotine. The standard curve was linear over a range of 10-500 yg/ml with a relative standard deviation of 95 % for 10-50 yg/ml. 

Further investigations, notably by Petrie 7], strongly suggested nicotine (3) as the principal alkaloid of the leaves pituri was later shown to contain both 3 and nornicotine (4) as well as other minor alkaloids in varying amounts [8,9. The alkaloids are present in the leaves as salts, and aboriginal experience had found that the maximum stimulating effect was obtained by adding wood ashes, which would result in release of the free bases. 

Over sixty species of Nicotiana exist that produce nicotine alkaloids (nicotine, nornicotine, anatabine, anabasine). Nicotine is the predominant alkaloid in over 50% of the Nicotiana species. Nornicotine is the major alkaloid in about 30% to 40% of Nicotiana species. Anabasine and anatabine are not usually the principal alkaloids in Nicotiana (17B05). Tobaccos that accumulate and have high levels of alkaloids tend to also have accumulations of minor alkaloids, for example, cotinine, myosmine, nicotyrine, 2,3 -bipyridine, and numerous derivatives of the major alkaloids, for example, alkyl, acyl, and nitroso derivatives of nicotine and the other... 

C9H10N2, Mr 149.19, mp. 40.5-42°C. A toxic minor alkaloid from the group of the tobacco alkaloids. It occurs in Nicotiana species. M. is formed biosynthet-ically by dehydrogenation of nornicotine. 

Nornicotine and anabasine count amongthe minor alkaloids of tobacco. Whereas Nkotiana species contain the (S)-nornicotine, Duboisia hopwoodii produces the (J )-enantiomer. Anabasine is with up to 2.6% the principal alkaloid of Anabasis aphylla. The anabasine content in Nkotiana glauca is comparatively high and reaches 1 %. 

Miyano M, Matsushita H, Yasumatsu N, Nishida K (1979) New minor alkaloids in burley tobacco (Nicotiana tabacum) Agric Biol Chem 43 1607-1608 Miyano M, Yasumatsu N, Matsushita H, Nishida K (1981) l -(6-Hydroxyoctanoyl)nomicotine and l -(7-hydroxyoctanoyl)nornicotine, two new alkaloids from Japanese domestic tobacco. Agric Biol Chem 45 1029-1032... 

The most important natural sources of minor tobacco alkaloids are from Nicotiana species, and at least eight minor tobacco alkaloids are shown in Figure 1. Since the chemical structures and physical properties of these minor tobacco alkaloids are similar to that of nicotine, some of them are shown to exhibit similar pharmacological activities as those of nicotine, although with a much lower potency. Table 2 shows their relative molar potency in some pharmacological systems. When nornicotine or anabasine was applied to the cat cervical ganglion, initial stimulation was followed by paralysis. On the autonomic ganglion and neuromuscular junction, nornicotine is only one-fifth to one-tenth as active as nicotine. Both nornicotine and anabasine have vaso-depressor action and affect the respiratory system. 

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